Identification ("ID") apparatus and methods are used in many varied applications including, for instance, in locator systems, monitoring systems, and security systems. Most of these systems associate a unique code with a particular person or object which is to be identified. The ID apparatus is typically carried by or affixed to the person or object, which either displays or otherwise indicates the unique code associated with the person or object.
Existing identification apparatus and methods oftentimes utilize radio frequency signals in which the unique code is utilized to develop a modulated signal which uniquely identifies the person or object. In these applications, a signal generator is carried by or affixed to the person or object identified by the unique code, and a modulated signal is generated to identify the person or object. Receiver circuitry positioned to receive the modulated signal generated by the signal generator identifies the person or object associated with the unique code once the modulated signal is received and demodulated.
In some instances, the receiver circuitry comprises transceiver circuitry operative both to generate modulated signals and to receive modulated signals, and the signal generator comprises transponder circuitry operative to generate the modulated signal responsive to times in which modulated signals generated by the transceiver circuitry are received by the transponder circuitry.
Transponder circuitry formed of circuitry capable of low power level operation can be powered by the energy of the particular radio frequency signals transmitted thereto by a transmitter. When the particular radio frequency signal is received by the transponder, circuitry of the transponder converts the energy of the received radio frequency signal into a form suitable for powering the various control and logic functions as well as the transmitter circuitry of the transponder. As the transponder circuitry is powered by the energy of the particular radio frequency signal, the transponder modulates the radio frequency carrier signal with a unique code only when the transponder is positioned to receive the signal transmitted thereto, and the signal transmitted thereto is greater than a predetermined threshold energy level.
The unique code associated with a particular object or person is stored in the circuitry of the transponder. In some instances, the unique code is stored in the circuitry of the transponder by forming specific circuit connections which make up the unique code. For instance, fused connections may be established with a laser device to form a unique code word. Alternatively, a memory element, such as an electrically programmable read only memory ("EPROM"), may be programmed to store the unique code.
Such existing techniques require that the unique code be stored or programmed during assembly of the transponder. Customization of the transponder circuitry for particular needs is therefore somewhat difficult as the unique code must be known at the time of the assembly of the transponder circuitry. Accordingly, when the transponder circuitry of the electronic identification apparatus needs to be customized or adapted for a particular purpose, the customization cannot occur at a retail level. Additionally, once the unique code is stored in the transponder circuitry, alteration can be effectuated, if at all, only with significant effort. Utilizing existing techniques, storage of a substitute code in the transponder circuitry requires reassembly of the transponder circuitry.
It is with respect to these considerations and other background information relative to existing identification apparatus that the significant improvements of the present invention have evolved.